Thank you so much for your responses! My travel agent had the same idea to get it in writing from carnival. She called this afternoon and said I should be fine- she got an email response from somebody high up at carnival that said I could use the birth card as long as it's certified. She has her name and contact information and said to print it off and take it with me! So I feel much more secure now. As soon as we get back from this cruise I'm gonna take my birthcard and go get my passport- I don't ever want to go through this again! Thanks again for your advice!